Alzheimer’s disease biomarkers predict rapid cognitive decline in very old adults

Cognitive decline in very old adults has been considered for decades to be an almost inevitable consequence of aging. In clinical practice, this has contributed to many memory problems in patients over age 80 being interpreted as a natural part of aging, without further investigation into their cause. However, this view is increasingly being challenged as knowledge of neurodegenerative diseases advances and more accurate tools for their detection become available.

A study led by researchers at the Sant Pau Research Institute (IR Sant Pau) and recently published in Neurology provides new evidence on the value of Alzheimer's disease biomarkers in this age group. The study, which focused on people aged 80 and older with mild cognitive impairment, shows that the presence of Alzheimer's disease biology-determined using biomarkers in cerebrospinal fluid and blood-is not only common but is also consistently associated with a greater risk of more rapid cognitive decline and progression to dementia.

These findings challenge the still widespread belief that biomarkers have limited value at very advanced ages because of the coexistence of multiple conditions. On the contrary, the study shows that, even within this more clinically complex context, identifying the underlying pathology continues to provide relevant information about patients' progression.

"Not every memory problem after age 80 is normal, and assuming that it is can lead to the underdiagnosis of diseases such as Alzheimer's," says Dr. Ignacio Illán-Gala, a researcher with the Neurobiology of Dementias Group at IR Sant Pau, a neurologist at Sant Pau Hospital, and one of the study's authors. "We need to overcome the influence of ageism in the care of these patients and move toward a more accurate diagnosis, including at advanced ages," he adds.